Walking Two Dogs
The state of the art of walking and controlling two dogs with a single handle is well known. The basic idea is a single handle with a short extension leash that ends in a swivel snap hook attached to a two-leash coupler. Instead (or in addition) the two-leash coupler itself can have a swivel or other rotatable connector at its upper end. When a short length coupler is used, two normal length leashes can be attached to the coupler's lower ends and at the other ends with swivel snap hooks to dog collars or harnesses. This setup allows the dogs to roam freely within the leash length radius. Most two-dog setups however, also those available commercially, consist of a handle with a short extension and a swivel end, a shorter or normal leash in-between, then a short two-leash coupler. This setup keeps the two dogs close together and restricts their roaming space. Each dog can change position in the team of two and the swivel(s) will automatically untangle. There are many variations and patents for two-dog leash setups and they tend to work well due to the rotatable swivels. A swivel is perfect for automatic untangling of two leashes. However by itself or even if used in multiples cannot automatically resolve all possible entanglements when using three or more leashes.
Walking Three Dogs
The state of the art of walking three dogs with a single handle however is generally not well known. The reason may be that these setups don't work that well or are elaborate and expensive and don't get many good reviews which restricts their sales and the public's knowledge. Many US and foreign patents however do claim that their leash arrangements for two dogs also avoid or resolve entanglements for three (or more) dogs. There are three-dog tripler leashes available commercially, having a swivel at the top with three short leashes. In another three-dog setup, a two-leash coupler is added and connected to a second two-leash coupler, with one dog on the higher and two dogs close together on the lower coupler.
Incomplete Solutions for Three or More Dogs
Examination of these patents and the commercially available handles with coupler and tripler leashes shows that the setups often can untangle some or many of the possible entanglement combinations automatically, however not all of them. Some setups are designed to also keep the leashes apart to avoid entanglements and this also helps, but sometimes at the cost of constraining the dogs on short leashes. It also does not prevent all possible entanglements. Another observation is that many of these setups seem complex or expensive.
When three-dog setups only work for some of the possible entanglement combinations, the handler will likely still encounter several entanglements during a walk. These will need to be untangled manually by uncoupling one or more dogs. That is very unsafe, time-consuming and frustrating. It also means the handler cannot fully trust the device or system and may become fearful of walking three dogs and therefore walk the dogs less often. A good system should resolve all possible entanglements, allow the dogs to roam free within the radius of their leash length and allow the handler to continue walking the dogs.
All entanglements with three dogs can be avoided when the length of the three-dog tripler leashes or other end leashes is kept very short, which is often done in the prior art. The dogs are kept side-by-side and constrained so much that they cannot walk over or under any of the other leashes. This is the opposite of ‘free roaming’ In the case of male dogs this does not allow enough room to urinate in the usual fashion and the dog may urinate against the neighboring dog. It is believed that most handlers prefer that their dogs enjoy their walk more by having lots of room to roam, sniff, play and do their business.
An explanation follows on why the three or more dog setups in the state of the art do not work fully for all possible entanglements. For example, looking at the setup in FIG. 7 of U.S. Pat. No. 6,237,539 to Sporn, two dogs are on short leashes and the third dog is on a longer leash. Using the numbers 14, 15, and 21 for the three dogs, any of the three dogs can get entangled with any one of the others. The possible entanglements then are: 14 with 15 (will untangle automatically due to the swivel); 21 with the twin team 14-15 (will untangle automatically due to the swivels); 21 with 15 (cannot untangle as the untangle operation is blocked by 14); and 21 with 14 (cannot untangle as the untangle operation is blocked by 15).
Of the possible entanglements, half get resolved automatically, the other half are blocked, unless the two short leashes 14 and 15 are so short that 14 cannot cross with 15, and 21 cannot cross with either 14 or 15. More elaborate setups such as in the Gish and Prendes patents show similar shortcomings. They do automatic untangling but do not avoid or untangle all possible entanglement combinations and/or keep the dogs restricted to a small roaming space.
None of the prior art and available triplers have full untangle capability for three or more dogs. They do not resolve all possible entanglements and/or fail to allow full motion for each individual leash, or they may get around these by constraining dogs to very short leashes and do not allow the dogs to roam free within a normal leash length radius. When an entanglement with a prior art system does happen and is not resolved, the handler is faced with undoing a tangled mess and cannot continue walking the dogs. These are big disadvantages.